Shower Presentations with R Markdown

Why we need a shoeprints database?

• What are reliable and accurate methods to quantify the similarity between two outsole prints?
• How robust are those methods to degradation of the crime scene print?
• What is the best instrument to “measure” outsole images? (We are using at least five different instruments).
• What is the persistence of outsole patterns over time? Or, can we identify the source of a print even after the shoe has been used for period of weeks or months?

Details

• Provide a pair of shoes to 160 persons (ISU students, staff, faculty and external)
• Roughly half men and half women
• Half one shoe pattern and half the other
• Take measurements every six weeks (baseline + four times)

Shoe models

• Contrained to:
  • current and future availability
  • One athletic and one more casual
• Nike Winflow 4 (left)
• Adidas Seeley (right)

Restrictions for impressions

• Time it takes to take each impression
• Adapt to schoolyear dates
• Tidiness of the space

Pressure Heatmat

• Obtain pressure map with Matscan pressure sensing mat by Tekscan
• Only at the beginning of the study
• 4 files per foot: JPEG, AVI, CSV (single frame), CSV (300 frames)

3D Scans

• Taken with EinScan Pro+ 3D scanner)
• Format: STL
• 2 scans per shoe

2D Scans

• Taken with EverOS footwear scanner
• Format: TIFF
• Modes: Detailed and quick
• 2 per shoe per mode

High Resolution Picture

• Modes: 2 (different lighting)
• Format: TIFF

Film Prints

• Procedure from Israeli Police
• Modes: two per shoe
• 1 film per shoe per mode

Paper Prints

• Stepping on paper after applying fingerprints powder
• Modes: Detailed, walking, stomping, twisting
• 1 impression per mode

Vinyl Impression

• Done right after paper prints

Other Considerations

Other Considerations

• No way to measure within subject variability (only one pair of shoes was asssigned to each subject)
• Two different patterns are being considered
• Two shoe sizes are being considered for every gender
• Weather might affect the experiment
• The person who takes the impression could be another factor